Both state governments and individual consumers are striving for increased energy efficiency, so it's natural to wonder how much progress is being made.
WalletHub recently analyzed data on cars and homes to determine which states were the most energy efficient.
The study ranked the states in terms of both cars and homes, and assigned an overall ranking based on a combination of the two scores.
The results showed Vermont to be the most-efficient state--it ranked fourth in car efficiency, and second in home efficiency.
According to the study, the most-efficient state for cars was Florida, while Utah came out on top in home-efficiency category.
Despite strict environmental regulations and strong incentives for plug-in electric cars, California was only ranked fourth overall. It had the fifth most-efficient car fleet, and was 14th in the rankings for homes.
Photovoltaic solar panels on roof of Honda Smart Home at UC-Davis, California
In terms of overall energy efficiency, the worst state was South Carolina. Louisiana ranked last for homes, while North Dakota was found to have the least efficient car fleet--likely due to a very high proportion of truck ownership among its citizens.
Alaska and Hawaii, as well as the District of Columbia, were not included in the study due to "data limitations."
For the 48 states included, automotive energy efficiency was calculated by dividing annual vehicle miles traveled by the total amount of gasoline consumed in gallons.
Diesel, alternative fuels, and any energy used to generate electricity for plug-in cars were presumably left out of the calculations--although they would act to lower the gasoline-consumption figure used to calculate a state's efficiency.
For homes, researchers divided total residential energy consumption per capita by annual degree days--an estimation of home heating or cooling energy demand based on temperature data from the National Weather Service.